Daniele Suzzi | Graz University of Technology (original) (raw)

Papers by Daniele Suzzi

Chemical Engineering Science, Jan 1, 2010

Spray coating is frequently used in the pharmaceutical industry to control the release of the act... more Spray coating is frequently used in the pharmaceutical industry to control the release of the active pharmaceutical ingredient of a tablet or to mask its taste. The uniformity of the coating is of significant importance, as the coating usually has critical functional properties. However, coating uniformity is difficult to predict without significant experimental work, and even advanced particle simulations need to be augmented by CFD models to fully describe the coating uniformity on a single tablet.

Understanding mass transfer effects (e.g., condensation and absorption) of hydrogen peroxide is e... more Understanding mass transfer effects (e.g., condensation and absorption) of hydrogen peroxide is essential for clean room decontamination technology. For example, absorption of hydrogen peroxide in polymers often causes unwanted effects in the final aeration phase of a decontamination cycle. This currently leads to significant challenges in the design and operation of clean rooms or isolators. We address here the absorption of H 2 O 2 in polymers, which is a key for an understanding of mass transfer effects. Specifically, we developed a novel experimental setup to measure the desorption rate from a polymer sheet. Together with a model for the diffusion in a polymer, we are able to theoretically predict the absorption and desorption kinetics of hydrogen peroxide. We then performed measurements of still unknown properties of hydrogen peroxide in polymers, i.e., the saturation concentration and the diffusion coefficient using our experimental setup. As expected, the diffusion in the polymer is the rate-limiting step for the absorption and the release of H 2 O 2 . We find that considerable amounts of H 2 O 2 can be absorbed in certain polymers on a time scale of less than an hour and may lead to a temporary violation of the Occupational Safety and Health Administration safety level in a typical clean room.

aiche.confex.com

Nucleation and transport of particles in multiphase reactors are two important mechanisms that si... more Nucleation and transport of particles in multiphase reactors are two important mechanisms that significantly influence the final product properties. Modeling these mechanisms is, however, extremely challenging and different approaches exist for the treatment of the particle ...

In this study a model for the prediction of polyacrylic acid/protamine nanoparticle precipitation... more In this study a model for the prediction of polyacrylic acid/protamine nanoparticle precipitation was developed, which constitutes the first numerical approach for modeling the precipitation of organic nanoparticles. Due to the complexity of the process, a spatial resolution (i.e., a simulation via computational fluid dynamics) was not the target. For the description of the precipitation process, population balance equations, accounting for nucleation, growth and aggregation were used and coupled with the engulfment model for mixing. Furthermore, experiments have been carried out by turbulent mixing of precursors in a vortex mixer. Measurements of the resulting particle size distributions and of the final concentrations in the liquid were performed. Finally, by selecting unknown parameters, it was possible to achieve a good agreement of experimental and numerical results. It was found that the formation of the electrostatic surface charge, caused by a layer of protamine on the particle surface, cannot be described instantaneously. Small deviations in the final liquid concentrations and particle size distributions are probably caused by the significant simplifications introduced by the engulfment model and by the description of the solid/liquid equilibrium. However, the presented model may serve as a basis for further development, i.e., by replacing the engulfment model by more sophisticated approaches, e.g., via computational fluid dynamics.

Heat Transfer: Volume 3, 2008

ABSTRACT The numerical prediction of underhood local temperatures represents a challenging field ... more ABSTRACT The numerical prediction of underhood local temperatures represents a challenging field in the development of passenger cars. The reliability of computational fluid dynamics (CFD) results is depending upon numerics and employing appropriate physical models which can strongly affect the quality of results and the overall simulation time. The purpose of this paper is to analyze and validate the simulation of heat transfer phenomena in a vehicle’s underbody through the comparison with experimental data. The measurements are obtained from thermal sensors mounted on a passenger car during a highway drive. Furthermore, the radiative boundary conditions are defined through the post-processing of thermographic camera images. The numerical results of a commercial CFD code are finally compared with the experimental data on surface temperatures of the vehicle’s underbody.

Industrial & Engineering Chemistry …, Jan 1, 2010

In our work we focus on the Euler-Lagrange strategy to simulate bubbly flows and fast chemical re... more In our work we focus on the Euler-Lagrange strategy to simulate bubbly flows and fast chemical reactions. We use a film model to account for fast, multi-step chemical reactions near the gas-liquid interface. A combination of such a film model with Euler-Lagrange simulations for bubbly flows has not been used before. Also, we account for micro-mixing effects with respect to chemical reactions in the liquid bulk by solving for the variance of the concentration field. To validate our model predictions for multiphase flow and reactive mixing, we compare our results with literature data and find excellent agreement.

Heat Transfer: Volume 3, 2008

ABSTRACT The numerical prediction of underhood local temperatures represents a challenging field ... more ABSTRACT The numerical prediction of underhood local temperatures represents a challenging field in the development of passenger cars. The reliability of computational fluid dynamics (CFD) results is depending upon numerics and employing appropriate physical models which can strongly affect the quality of results and the overall simulation time. The purpose of this paper is to analyze and validate the simulation of heat transfer phenomena in a vehicle’s underbody through the comparison with experimental data. The measurements are obtained from thermal sensors mounted on a passenger car during a highway drive. Furthermore, the radiative boundary conditions are defined through the post-processing of thermographic camera images. The numerical results of a commercial CFD code are finally compared with the experimental data on surface temperatures of the vehicle’s underbody.

International Symposium on Advances in Computational Heat Transfer, 2008

Soft Matter, 2011

In this study a model for the prediction of polyacrylic acid/protamine nanoparticle precipitation... more In this study a model for the prediction of polyacrylic acid/protamine nanoparticle precipitation was developed, which constitutes the first numerical approach for modeling the precipitation of organic nanoparticles. Due to the complexity of the process, a spatial resolution (i.e., a simulation via computational fluid dynamics) was not the target. For the description of the precipitation process, population balance equations, accounting for nucleation, growth and aggregation were used and coupled with the engulfment model for mixing. Furthermore, experiments have been carried out by turbulent mixing of precursors in a vortex mixer. Measurements of the resulting particle size distributions and of the final concentrations in the liquid were performed. Finally, by selecting unknown parameters, it was possible to achieve a good agreement of experimental and numerical results. It was found that the formation of the electrostatic surface charge, caused by a layer of protamine on the particle surface, cannot be described instantaneously. Small deviations in the final liquid concentrations and particle size distributions are probably caused by the significant simplifications introduced by the engulfment model and by the description of the solid/liquid equilibrium. However, the presented model may serve as a basis for further development, i.e., by replacing the engulfment model by more sophisticated approaches, e.g., via computational fluid dynamics.

Journal of Pharmaceutical Innovation, 2011

Abstract Understanding mass transfer effects (eg, condensation and absorption) of hydrogen peroxi... more Abstract Understanding mass transfer effects (eg, condensation and absorption) of hydrogen peroxide is essential for clean room decontamination technology. For example, absorption of hydrogen peroxide in polymers often causes unwanted effects in the final aeration ...

Industrial & Engineering Chemistry Research, 2010

In our work, we focus on the Euler−Lagrange strategy to simulate bubbly flows and fast chemical r... more In our work, we focus on the Euler−Lagrange strategy to simulate bubbly flows and fast chemical reactions. We propose a film model to account for fast, multistep chemical reactions near the gas−liquid interface. A combination of such a film model with Euler−Lagrange simulations ...

Chemical Engineering …, Jan 1, 2011

Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a ta... more Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a tablet or a granule containing active pharmaceutical ingredients (APIs). Inter-and intra-tablet variability of film coating is a critical issue in the production of solid oral dosage forms. In fact, inhomogeneity in the coating thickness can lead to significant variations in the delivery rate of active pharmaceutical ingredients and compromise the functional attributes of the tablet film. Although attempts have been made to use numerical approaches to analyze this complex problem, at present the uniformity of coating thickness is difficult to predict without expensive experimental work.

Journal of Pharmaceutical Innovation, 2012

Chemie Ingenieur Technik, 2009

Mixing and fast chemical reactions in sparged stirred tanks are of great importance in the chemic... more Mixing and fast chemical reactions in sparged stirred tanks are of great importance in the chemical industry. If multiple reaction steps occur within one apparatus, a detailed understanding of local mixing is crucial to precisely control the reaction network. However, a single, rigorous framework describing the interaction between reactions, mass transfer and liquid phase mixing is currently not available in the literature. This is mainly because experimental methods as well as numerical simulations are extremely demanding, especially with respect to micro-and mesomixing in bubble swarms. For example, fully resolved 3D simulations of reacting bubble swarms with complex reactions are still challenging. Hence, our previous work was based on 2D direct numerical simulations of bubbly flows, and three-dimensional effects were ignored completely. In this work it is our intension to assess micro-and mesomixing effects by using highfidelity numerical simulations. We use different simulation approaches that allow us to simulate bubbly flows as well as scalar transport in high detail. Our work includes direct numerical simulation of bubble wake phenomena and large eddy simulations combined with Lagrangian bubble tracking to study bubble plume effects. The major achievement presented in this work is the use different concepts for assessing mixing quality in complex gas-liquid flows. Hence, we are one of the first groups that is able to shed some light on the interaction of multiphase flow and local mixing effects.

European Journal of Pharmaceutical Sciences, 2011

A combined Quality by Design (QbD) and Discrete Element Model (DEM) simulation-approach is presen... more A combined Quality by Design (QbD) and Discrete Element Model (DEM) simulation-approach is presented to characterize a blending unit operation by evaluating the impact of formulation parameters and process variables on the blending quality and blending end point. Understanding the variability of both the API and the excipients, as well as their impact on the blending process are critical elements for blending QbD. In a first step, the QbD-methodology is systematically used to (1) establish the critical quality attribute content uniformity and to link this CQA to its surrogate blend homogeneity, (2) identify potentially critical input factors that may affect blending operation quality and (3) risk-rank these factors to define activities for process characterization. Subsequently, a DEM-simulation-based characterization of the blending process is performed. A statistical evaluation is finally presented, relating blend homogeneity of systems with low particle number to the regulatory requirements. Data are then used to map out a three-dimensional knowledge space, providing parameters to define a design space and set up an appropriate control strategy.

Chemical Engineering Science

Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a ta... more Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a tablet or a granule containing active pharmaceutical ingredients (APIs). Inter-and intra-tablet variability of film coating is a critical issue in the production of solid oral dosage forms. In fact, inhomogeneity in the coating thickness can lead to significant variations in the delivery rate of active pharmaceutical ingredients and compromise the functional attributes of the tablet film. Although attempts have been made to use numerical approaches to analyze this complex problem, at present the uniformity of coating thickness is difficult to predict without expensive experimental work.

Chemical Engineering Science, 2010

Spray coating is frequently used in the pharmaceutical industry to control the release of the act... more Spray coating is frequently used in the pharmaceutical industry to control the release of the active pharmaceutical ingredient of a tablet or to mask its taste. The uniformity of the coating is of significant importance, as the coating usually has critical functional properties. However, coating uniformity is difficult to predict without significant experimental work, and even advanced particle simulations need to be augmented by CFD models to fully describe the coating uniformity on a single tablet.

Chemical Engineering Science, 2011

Oil-in-water (O/W) emulsions produced by static mixers in the laminar flow regime are characteriz... more Oil-in-water (O/W) emulsions produced by static mixers in the laminar flow regime are characterized for their oil drop size spectra. The emulsions are used in the first process step for the production of microspheres for pharmaceutical applications by the emulsion extraction method. However, emulsion generation by static mixers in the laminar flow regime is rarely discussed in the scientific literature.

Chemical Engineering Science, Jan 1, 2010

Spray coating is frequently used in the pharmaceutical industry to control the release of the act... more Spray coating is frequently used in the pharmaceutical industry to control the release of the active pharmaceutical ingredient of a tablet or to mask its taste. The uniformity of the coating is of significant importance, as the coating usually has critical functional properties. However, coating uniformity is difficult to predict without significant experimental work, and even advanced particle simulations need to be augmented by CFD models to fully describe the coating uniformity on a single tablet.

Understanding mass transfer effects (e.g., condensation and absorption) of hydrogen peroxide is e... more Understanding mass transfer effects (e.g., condensation and absorption) of hydrogen peroxide is essential for clean room decontamination technology. For example, absorption of hydrogen peroxide in polymers often causes unwanted effects in the final aeration phase of a decontamination cycle. This currently leads to significant challenges in the design and operation of clean rooms or isolators. We address here the absorption of H 2 O 2 in polymers, which is a key for an understanding of mass transfer effects. Specifically, we developed a novel experimental setup to measure the desorption rate from a polymer sheet. Together with a model for the diffusion in a polymer, we are able to theoretically predict the absorption and desorption kinetics of hydrogen peroxide. We then performed measurements of still unknown properties of hydrogen peroxide in polymers, i.e., the saturation concentration and the diffusion coefficient using our experimental setup. As expected, the diffusion in the polymer is the rate-limiting step for the absorption and the release of H 2 O 2 . We find that considerable amounts of H 2 O 2 can be absorbed in certain polymers on a time scale of less than an hour and may lead to a temporary violation of the Occupational Safety and Health Administration safety level in a typical clean room.

aiche.confex.com

Nucleation and transport of particles in multiphase reactors are two important mechanisms that si... more Nucleation and transport of particles in multiphase reactors are two important mechanisms that significantly influence the final product properties. Modeling these mechanisms is, however, extremely challenging and different approaches exist for the treatment of the particle ...

In this study a model for the prediction of polyacrylic acid/protamine nanoparticle precipitation... more In this study a model for the prediction of polyacrylic acid/protamine nanoparticle precipitation was developed, which constitutes the first numerical approach for modeling the precipitation of organic nanoparticles. Due to the complexity of the process, a spatial resolution (i.e., a simulation via computational fluid dynamics) was not the target. For the description of the precipitation process, population balance equations, accounting for nucleation, growth and aggregation were used and coupled with the engulfment model for mixing. Furthermore, experiments have been carried out by turbulent mixing of precursors in a vortex mixer. Measurements of the resulting particle size distributions and of the final concentrations in the liquid were performed. Finally, by selecting unknown parameters, it was possible to achieve a good agreement of experimental and numerical results. It was found that the formation of the electrostatic surface charge, caused by a layer of protamine on the particle surface, cannot be described instantaneously. Small deviations in the final liquid concentrations and particle size distributions are probably caused by the significant simplifications introduced by the engulfment model and by the description of the solid/liquid equilibrium. However, the presented model may serve as a basis for further development, i.e., by replacing the engulfment model by more sophisticated approaches, e.g., via computational fluid dynamics.

Heat Transfer: Volume 3, 2008

ABSTRACT The numerical prediction of underhood local temperatures represents a challenging field ... more ABSTRACT The numerical prediction of underhood local temperatures represents a challenging field in the development of passenger cars. The reliability of computational fluid dynamics (CFD) results is depending upon numerics and employing appropriate physical models which can strongly affect the quality of results and the overall simulation time. The purpose of this paper is to analyze and validate the simulation of heat transfer phenomena in a vehicle’s underbody through the comparison with experimental data. The measurements are obtained from thermal sensors mounted on a passenger car during a highway drive. Furthermore, the radiative boundary conditions are defined through the post-processing of thermographic camera images. The numerical results of a commercial CFD code are finally compared with the experimental data on surface temperatures of the vehicle’s underbody.

Industrial & Engineering Chemistry …, Jan 1, 2010

In our work we focus on the Euler-Lagrange strategy to simulate bubbly flows and fast chemical re... more In our work we focus on the Euler-Lagrange strategy to simulate bubbly flows and fast chemical reactions. We use a film model to account for fast, multi-step chemical reactions near the gas-liquid interface. A combination of such a film model with Euler-Lagrange simulations for bubbly flows has not been used before. Also, we account for micro-mixing effects with respect to chemical reactions in the liquid bulk by solving for the variance of the concentration field. To validate our model predictions for multiphase flow and reactive mixing, we compare our results with literature data and find excellent agreement.

Heat Transfer: Volume 3, 2008

ABSTRACT The numerical prediction of underhood local temperatures represents a challenging field ... more ABSTRACT The numerical prediction of underhood local temperatures represents a challenging field in the development of passenger cars. The reliability of computational fluid dynamics (CFD) results is depending upon numerics and employing appropriate physical models which can strongly affect the quality of results and the overall simulation time. The purpose of this paper is to analyze and validate the simulation of heat transfer phenomena in a vehicle’s underbody through the comparison with experimental data. The measurements are obtained from thermal sensors mounted on a passenger car during a highway drive. Furthermore, the radiative boundary conditions are defined through the post-processing of thermographic camera images. The numerical results of a commercial CFD code are finally compared with the experimental data on surface temperatures of the vehicle’s underbody.

International Symposium on Advances in Computational Heat Transfer, 2008

Soft Matter, 2011

In this study a model for the prediction of polyacrylic acid/protamine nanoparticle precipitation... more In this study a model for the prediction of polyacrylic acid/protamine nanoparticle precipitation was developed, which constitutes the first numerical approach for modeling the precipitation of organic nanoparticles. Due to the complexity of the process, a spatial resolution (i.e., a simulation via computational fluid dynamics) was not the target. For the description of the precipitation process, population balance equations, accounting for nucleation, growth and aggregation were used and coupled with the engulfment model for mixing. Furthermore, experiments have been carried out by turbulent mixing of precursors in a vortex mixer. Measurements of the resulting particle size distributions and of the final concentrations in the liquid were performed. Finally, by selecting unknown parameters, it was possible to achieve a good agreement of experimental and numerical results. It was found that the formation of the electrostatic surface charge, caused by a layer of protamine on the particle surface, cannot be described instantaneously. Small deviations in the final liquid concentrations and particle size distributions are probably caused by the significant simplifications introduced by the engulfment model and by the description of the solid/liquid equilibrium. However, the presented model may serve as a basis for further development, i.e., by replacing the engulfment model by more sophisticated approaches, e.g., via computational fluid dynamics.

Journal of Pharmaceutical Innovation, 2011

Abstract Understanding mass transfer effects (eg, condensation and absorption) of hydrogen peroxi... more Abstract Understanding mass transfer effects (eg, condensation and absorption) of hydrogen peroxide is essential for clean room decontamination technology. For example, absorption of hydrogen peroxide in polymers often causes unwanted effects in the final aeration ...

Industrial & Engineering Chemistry Research, 2010

In our work, we focus on the Euler−Lagrange strategy to simulate bubbly flows and fast chemical r... more In our work, we focus on the Euler−Lagrange strategy to simulate bubbly flows and fast chemical reactions. We propose a film model to account for fast, multistep chemical reactions near the gas−liquid interface. A combination of such a film model with Euler−Lagrange simulations ...

Chemical Engineering …, Jan 1, 2011

Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a ta... more Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a tablet or a granule containing active pharmaceutical ingredients (APIs). Inter-and intra-tablet variability of film coating is a critical issue in the production of solid oral dosage forms. In fact, inhomogeneity in the coating thickness can lead to significant variations in the delivery rate of active pharmaceutical ingredients and compromise the functional attributes of the tablet film. Although attempts have been made to use numerical approaches to analyze this complex problem, at present the uniformity of coating thickness is difficult to predict without expensive experimental work.

Journal of Pharmaceutical Innovation, 2012

Chemie Ingenieur Technik, 2009

Mixing and fast chemical reactions in sparged stirred tanks are of great importance in the chemic... more Mixing and fast chemical reactions in sparged stirred tanks are of great importance in the chemical industry. If multiple reaction steps occur within one apparatus, a detailed understanding of local mixing is crucial to precisely control the reaction network. However, a single, rigorous framework describing the interaction between reactions, mass transfer and liquid phase mixing is currently not available in the literature. This is mainly because experimental methods as well as numerical simulations are extremely demanding, especially with respect to micro-and mesomixing in bubble swarms. For example, fully resolved 3D simulations of reacting bubble swarms with complex reactions are still challenging. Hence, our previous work was based on 2D direct numerical simulations of bubbly flows, and three-dimensional effects were ignored completely. In this work it is our intension to assess micro-and mesomixing effects by using highfidelity numerical simulations. We use different simulation approaches that allow us to simulate bubbly flows as well as scalar transport in high detail. Our work includes direct numerical simulation of bubble wake phenomena and large eddy simulations combined with Lagrangian bubble tracking to study bubble plume effects. The major achievement presented in this work is the use different concepts for assessing mixing quality in complex gas-liquid flows. Hence, we are one of the first groups that is able to shed some light on the interaction of multiphase flow and local mixing effects.

European Journal of Pharmaceutical Sciences, 2011

A combined Quality by Design (QbD) and Discrete Element Model (DEM) simulation-approach is presen... more A combined Quality by Design (QbD) and Discrete Element Model (DEM) simulation-approach is presented to characterize a blending unit operation by evaluating the impact of formulation parameters and process variables on the blending quality and blending end point. Understanding the variability of both the API and the excipients, as well as their impact on the blending process are critical elements for blending QbD. In a first step, the QbD-methodology is systematically used to (1) establish the critical quality attribute content uniformity and to link this CQA to its surrogate blend homogeneity, (2) identify potentially critical input factors that may affect blending operation quality and (3) risk-rank these factors to define activities for process characterization. Subsequently, a DEM-simulation-based characterization of the blending process is performed. A statistical evaluation is finally presented, relating blend homogeneity of systems with low particle number to the regulatory requirements. Data are then used to map out a three-dimensional knowledge space, providing parameters to define a design space and set up an appropriate control strategy.

Chemical Engineering Science

Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a ta... more Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a tablet or a granule containing active pharmaceutical ingredients (APIs). Inter-and intra-tablet variability of film coating is a critical issue in the production of solid oral dosage forms. In fact, inhomogeneity in the coating thickness can lead to significant variations in the delivery rate of active pharmaceutical ingredients and compromise the functional attributes of the tablet film. Although attempts have been made to use numerical approaches to analyze this complex problem, at present the uniformity of coating thickness is difficult to predict without expensive experimental work.

Chemical Engineering Science, 2010

Spray coating is frequently used in the pharmaceutical industry to control the release of the act... more Spray coating is frequently used in the pharmaceutical industry to control the release of the active pharmaceutical ingredient of a tablet or to mask its taste. The uniformity of the coating is of significant importance, as the coating usually has critical functional properties. However, coating uniformity is difficult to predict without significant experimental work, and even advanced particle simulations need to be augmented by CFD models to fully describe the coating uniformity on a single tablet.

Chemical Engineering Science, 2011

Oil-in-water (O/W) emulsions produced by static mixers in the laminar flow regime are characteriz... more Oil-in-water (O/W) emulsions produced by static mixers in the laminar flow regime are characterized for their oil drop size spectra. The emulsions are used in the first process step for the production of microspheres for pharmaceutical applications by the emulsion extraction method. However, emulsion generation by static mixers in the laminar flow regime is rarely discussed in the scientific literature.